The government accountability group Judicial Watch announced Thursday that it has sued the Department of Homeland Security for records dealing with the more than 36,000 convicted criminal aliens the Obama administration released last year.

The conservative group says it is suing because the government failed to respond to its Freedom of Information Act earlier this year about a Center for Immigration Studiesreport revealing criminal immigrant releases.

“This would be considered the worst prison break in American history, except it was sanctioned by the President and perpetrated by our own immigration officials,” former Senate Judiciary Committee chairman Lamar Smith (R-TX) said at the time of the report’s release.

In May, reacting to CIS’s report detailing the nearly 88,000 crimes for which the 36,007 released criminal immigrants were convicted — including homicide sexual assault kidnapping, aggravated assault, and drug convictions — Judicial Watch filed a FOIA request seeking a wide range of documents dealing with the criminal alien releases.